Prototype Of Antenna Research Articles

A broadband beam‐steerable Fabry–Pérot antenna employing water‐based reconfigurable partially reflective surface

AbstractA novel broadband water‐based Fabry–Pérot (FP) antenna with beam‐steerable technology is proposed. The antenna consists of a water‐based reconfigurable partially reflective surface (RPRS) and a source antenna. The proposed water‐based RPRS has 13 columns of microfluidic channels inside. The water‐based RPRS achieved 1‐D beam steering by regulating phase distribution through the injection of water into its microfluidic channels. The antenna has exhibited a 10‐dB impedance bandwidth from 5.07 to 6.46 GHz (a fractional bandwidth of 24.1%). This design achieves a beam steering from −11° to +11° in the elevation plane, with measured realised gains over 10 dBi. To verify the correctness of the design, an antenna prototype was fabricated. The measured results are in good agreement with the simulated results, confirming the accuracy of the design principle. The measured results demonstrate that the main beam of the antenna prototype tilts to −12° in the broadside direction.

Conformal multi-channel MIMO antenna for implantable leadless transcatheter pacing systems

This article presents a conformal multi-channel multiple-input-multiple-output (MIMO) antenna designed for a leadless transcatheter pacing system (TPS), operating across the medical implants communications services (MICS) band (401–406 MHz), the wireless medical telemetry services (WMTS) bands (0.608 GHz and 1.4 GHz), and the industrial, scientific and medical (ISM) bands (0.433 GHz, 0.915 GHz, and 2.45 GHz). The proposed antenna has a size of 19 mm × 10 mm × 0.068 mm (0.047λg × 0.025λg × 0.0001λg), and it is constructed on a thin polyimide substrate and wrapped around the TPS capsule’s inner wall, efficiently utilizing the inner space. For the simulation, the proposed antenna and TPS capsule containing dummy electronics are positioned within a homogeneous three-layered phantom (skin-fat-heart) with dielectric properties that mimic the human heart, as well as in a realistic heterogeneous voxel model (Gustav). The antenna is validated for a real environment using an ex-vivo setup comprised of fabricating the antenna prototype and measuring its performance metrics inside pork meat and phantom solution. The proposed MIMO antenna offers good isolation (>25 dB) between antenna elements, and the impedance bandwidths are 710 MHz (0.34 to 1.05 GHz), 560 MHz (1.26 to 1.82 GHz), and 990 MHz (2.01 to 3 GHz). Further, MIMO characteristics are evaluated, and antenna robustness and safety are tested by considering specific absorption rates using human voxel models. The proposed MIMO antenna is the thinnest conformal antenna designed to cover essential biotelemetry frequency bands, including low frequencies of 0.402 GHz and 0.433 GHz with circular polarization, which significantly reduces power consumption and improves transmission range, making it a viable candidate for wireless TPS applications.

A Wideband High-Gain All-Metal Antenna under Quad Resonances Realized by Folding a Simple Patch

This paper presents a novel wideband antenna with a simple structure comprising an integrated microstrip patch antenna (MPA) and three shorted microstrip patch antennas (SMPAs). These four radiators constitute an antenna that operates under quad resonances and achieves a wide frequency bandwidth. Since all units are electrically connected, the antenna can be easily fabricated by folding a single metallic strip to realize an all-metal antenna structure, leading to enhanced resistance to extreme environmental conditions and lower power loss. An antenna prototype was used to validate the proposed concept. The measurement results indicated that the proposed handmade structure, which employed probe excitation with overall electrical dimensions of 0.29λ × 0.27λ × 0.11λ, can acquire an impedance frequency bandwidth of 67% for <i>S</i><sub>11</sub> ≤ -10 dB from 1.6–3.2 GHz and achieve a maximum boresight gain of up to 10 dB. The wide frequency bandwidth, high gain, and simple structure make this antenna a promising candidate for wideband mobile systems.

A New Concept of Reconfigurable Antenna Structure Based on an Array of RF-MEMS Switches

A geometrical reconfigurable structure based on RF Micro-electro-mechanical switches (RF-MEMS) is proposed in this work. The structure is composed of an array of gold metallic patches interconnected together utilizing RF-MEMS switches in order to change its geometry and, consequently, the scattering parameters. In particular, the reconfigurability is achieved by activating multiple RF-MEMS switches, which enables the change in electrical length and, consequently, the resonance frequency of the structure. As a proof of concept, an experimental antenna prototype composed of an array of 7×7 elements interconnected by a set of RF-MEMS switches has been designed, fabricated numerically, and experimentally assessed. The structure can be set as an antenna or as other basic radio frequency components. The obtained experimental results are in good agreement with the simulations, with an error of less than 5% for the considered radiating structures. The quite promising results demonstrate the potential and flexibility of the proposed structure.

Substrate integrated waveguide differential antenna for full duplex applications

Abstract This paper presents a substrate-integrated waveguide (SIW) differential antenna for full duplex applications. The proposed antenna consists of two square SIW cavities named as outer and inner. The inner cavity is nested into the outer cavity. The outer cavity is differentially excited with a pair of coaxial feed lines, while the inner square patch is orthogonally excited with another pair of differential coaxial feed lines. This orthogonal feeding arrangement results in high isolation between the differential ports. The modified hybrid TE130/310 mode of the outer cavity radiates through a pair of arc-shaped slots at 9.35 GHz, while the TM01 mode of the inner square patch is responsible for the radiations at 8.65 GHz. The proposed antenna prototype is fabricated and measured for validation. Moreover, the designed antenna has a front-to-back ratio better than 22 dB and measured maximum gain values of 6.1 dBi and 7.6 dBi at 8.65 GHz (Port 2 ON) and 9.35 GHz (Port 1 ON), respectively.

Design of a Multiband Antenna Using Auxiliary Classifier Wasserstein Generative Adversarial Network for IoT Applications

ABSTRACTThe rapid expansion of Internet of Things (IoT) applications presents unprecedented challenges for antenna design, demanding solutions that are versatile, efficient, and capable of operating across multiple frequency bands. This paper addresses these challenges through the development of a design of a multiband antenna using Auxiliary Classifier Wasserstein Generative Adversarial Network for IoT applications (DMA‐ACWGAN‐IoT). Here, the Auxiliary Classifier Wasserstein Generative Adversarial Network (ACWGAN) is employed to generate synthetic data representing electromagnetic field distributions and antenna characteristics across various frequencies. The proposed metamaterial‐based Multiple‐Input Multiple‐Output (MIMO) antenna contains four discrete elements, each provided by a micro strip feed. The structures overall width and length are 60 and 52 mm. The metamaterial is printed on a patch and dispersed from the fields with the most effective coupling. The proposed structures strong impedance bandwidth works at 8.3 GHz, 10.8 GHz, 12.3 GHz, 13.7 GHz, 16.1 GHz, and 18.1 GHz, fabricating the proposed antenna prototype using a substrate made of FR‐4 material. The proposed DMA‐ACWGAN‐IoT design provides 6.5 dB maximum gain and 25.40%, 21.60%, and 20.05% higher efficiency compared to existing dual band antenna design with resonance frequency prediction under machine learning models (DBA‐PRF‐ML), machine learning verification depending on a distinctive SWB multiple slotted four‐port high isolated MIMO antenna loaded with metasurface for the applications of IoT (SWB‐MIMO‐IOT‐ML), and dual‐band miniaturized composite right–left‐handed transmission line ZOR antenna along machine learning method for microwave communication (DB‐ZORA‐MC‐ML).

Experimental prototype of mesh antenna based on digital twin technology

The ring mesh antenna plays an important role in the field of aerospace communication owing to its excellent performance characteristics, but faces the challenge of decreasing profile accuracy due to environmental and structural failures during in-orbit operation. Digital twin, a promising technology, can effectively monitor and adjust the antenna surface accuracy. In other words, by creating a digital model of the physical entity, real-time monitoring and adjustment can be made to maintain the electrical performance of the antenna. In this paper, a digital twin system for an experimental prototype of a ring mesh antenna is proposed. Firstly, we introduce the preliminaries of digital twin technology. Secondly, we propose a system framework based on a five-dimensional digital twin model. Then, a digitization software and a visualization interface are developed. Finally, according to efficiency analysis and simulation results, the feasibility of the system was verified. We demonstrate its effectiveness in terms of real-time monitoring and automatic mesh adjustment functions, and significantly improve the efficiency of the adjustment process. It provides a reference with significant value for the application of digital twin technology in the field of aerospace communication, which significantly advances the development of this field.

Asymmetric Coplanar Strip Loaded With Meander Lines for Multiband Operations Using ANN Optimization

ABSTRACTA miniaturized asymmetric coplanar strip fed with meander lines is developed for hexaband wireless applications. Multiband with compact size of the antenna is developed by using meander lines. The designed antenna is enhanced by an increased number of meander lines. The invented antenna is composed of three meander lines, it yields the antenna to excite 1.13, 2.35, 2.91, 3.46, 3.96, and 4.5 GHz, respectively. The prototype antenna is fed by ACS, which is printed on a 14 24 1.6 mm3 FR‐4 substrate and dielectric constant of Ɛr = 4.4. MATLAB tool is utilized in the ANN computation to amend the physical values of the antenna. The calibrated and simulated radiation attributes are identical with each other. The designed antenna provides distinguishing characteristics such as good reflection coefficient, impedance matching, and size miniaturization. It imparts empirical peak gains of 0.028 dBi at 1.14 GHz, 1.305 dBi at 2.35 GHz, 1.54 dBi at 2.86 GHz, 1.79 dBi at 3.43 GHz, 2.43 dBi at 3.96 GHz, and 2.58 dBi at 4.5 GHz, which is suitable for GSM/WLAN/WiMAX and C‐band wireless applications.

Material Selection and Design Methods for Flexible RFID Tag Antenna

In recent years, advancements in flexible printed electronics have significantly propelled the development of wearable devices, especially in areas of integration, comfort, and streamlined manufacturing. By incorporating electronic components and conductive coatings onto flexible substrates, circuits gain enhanced flexibility and some degree of stretchability. Among these circuits, radio frequency identification (RFID) tag antennas have emerged as a focal point in wearable device communication due to their adaptability in power selection and their compatibility with printed circuit technologies. When designing flexible and stretchable RFID tag antennas using printed electronics, two critical factors need to be addressed. The first is the antenna’s structural design, which must account for varying environments and usage contexts. The second is the development of the antenna prototype, involving the selection of conductive coatings and flexible substrates, as well as the printing processes and performance evaluation standards. This paper will explore common conductive coatings and substrate materials used in flexible printed electronics, along with the design methods of printed tag antennas for wearable applications. Lastly, a novel approach is proposed in which the flexible and stretchable RFID tag antenna itself functions as a strain sensor for posture or pressure detection. Unlike conventional strain sensors, this design eliminates the need for additional communication modules, offering a simplified structure that can be easily printed onto clothing, thereby streamlining the production process.

A single-feed circularly polarized antenna with a low vertical profile and hemispherical axial-ratio beam coverage

ABSTRACT A novel wide axial-ratio beamwidth (ARBW) circularly polarized (CP) antenna with a single layer substrate fed by a single probe is proposed. It consists of an inner annular slotted radiator containing eight outer sector units with arc branches, a ground plane, and eight grounded vias. The antenna has an ARBW covering the upper hemisphere and has a low vertical profile. The ultra-hemispherical ARBW is formed by ingeniously merging the endfire omnidirectional CP radiation pattern with the boresight CP radiation pattern. The two radiation patterns can be excited by a central coaxial probe without an additional feeding network. An antenna prototype of dimensions 1.15 × 1.15 × 0.02 (λ 0 3) is fabricated and measured to validate the design concept. Measured results show that the impedance bandwidth of the proposed antenna is 2.0% (3.328–3.394 GHz) and the 3 dB axial ratio (AR) bandwidth is 1.3% (3.332–3.374 GHz). The 3 dB AR beamwidth can cover more than 217° and the maximum gain is 0.79 dBic at 3.35 GHz. A good agreement between the simulated and measured results is obtained.

OPTIMASI BANDWIDTH MENGGUNAKAN STUB MATCHING IMPEDANSI PADA RANCANG BANGUN ANTENA MONOPOLE ULTRA-WIDEBAND

The microstrip monopole antenna design study was developed to support Ultra-Wideband (3.1GHz-10.6 GHz) wireless communication technology. This research aims to obtain a minimalist antenna prototype with the ability to operate in the UWB frequency region. Bandwidth optimization is carried out to increase data speed access capacity in wireless communications. The antenna design has two structures in the conductor layer of the RT DUROID 5880 type substrate material. The surface layer structure is a square patch with a transmission line and an impedance stub. For the bottom layer of the substrate, a structure forms the DGS technique. The simulation method is carried out on the antenna design to obtain parameters, such as bandwidth return loss -10dB is 1.29 (fractional) or 9700MHz (absolute) and bandwidth measurement results (absolute) (12,800 MHz-absolute), VSWR (1:2), input impedance at the 3.8GHz frequency (Zin=31.23Ω-j4.12Ω), and the 13.6GHz frequency (Zin=62.93Ω+j28.4Ω). For radiation polarization, the beam width is 116 degrees and the directional strength (Gain) value is 3.15dBi. The entire antenna has the performance characteristics of operating in the Ultra-Wideband spectrum at C-band, X-band and Ku-band frequencies. Omnidirectional polarization, vertical linear polarization, and low gain and minimalist support communication devices.

A Compact and Flexible Monopole Antenna with Controllable Bandwidth

In this paper, a compact antenna with flexible and controllable bandwidth characteristics is proposed. To ensure wide coverage along with an omnidirectional radiation pattern, a monopole structure was utilized as the primary radiating element of the proposed antenna. The monopole was fed using a coplanar waveguide technique to achieve a single-layer design. To alter the operating bandwidth, defined by a reflection coefficient of less than -10 dB, a single stub was directly connected to the feeding transmission line. By controlling the stub's length, matching performance in the high-frequency range was found to undergo significant degradation, indicating that the operating bandwidth could be controlled. Furthermore, for validation, two antenna prototypes were fabricated and measured under different circumstances. In the unbending mode, the design without the stub achieved a wideband of 51.6%, while the other design with the stub exhibited a narrower band of about 19.6%. Additionally, the antennas worked efficiently when operating in bending mode. It is also worth noting that the antenna gain and radiation pattern remained stable across the entire operating bandwidth.

Cost-Effective High Gain Wideband Antenna with Dual Partially Reflective Surface for 5G-mmWave Application

This research presents the performance improvement of the of rectangular patch microstrip antenna. The purpose is to increase gain and bandwidth with design on the PRS (Partially Reflective Surface) dual layer technique. There is a developing the low-cost substrate-based antennas suitable for 5G millimeter-wave. The prototype antenna achieves a maximum gain of 11.8 dBi at a frequency of 25.5 GHz. The gain increases by 6 dB throughout its operational frequency range, with an OBW (Overlap bandwidth) of 20.9%, covering frequencies from 24.0 GHz to 29.9 GHz. The performance achieved results indicate that the prototype antenna can be effectively utilized for 5G millimeter-wave communication applications in Thailand.

Compact VHF/UHF Ultrawideband Discone Antenna with Consistent Pattern.

A compact VHF/UHF ultrawideband discone antenna with consistent patterns is proposed in this article. The proposed antenna consists of a disk, a modified cone, an inverted cone, four shorting probes, and two sleeves. To improve the radiation angular distortion at high frequencies, two sleeves are inserted into the discone antenna. Higher-order modes are suppressed, and ultrawideband consistent patterns are obtained without antenna size increasing. An inverted cone and four shorting probes are introduced to achieve broadband and profile reduction. An antenna prototype is fabricated and measured. The proposed antenna possesses consistent patterns in a 11.36:1 bandwidth. The pattern nulls is improved by 26.1 dB. The antenna occupies a cylindrical volume of 0.227 λ0 (D) and 0.096 λ0 (H). It is a competitive candidate for future in-vehicle communication systems.

A compound reconfigurable series-fed microstrip antenna for satellite communication applications

PurposeThis paper aims to present an innovative reconfigurable series-fed microstrip antenna using radiofrequency positive intrinsic negative (RF PIN) diodes for cognitive S-band and C-band satellite communications. The antenna can dynamically reconfigure its frequency, polarization and radiation pattern to meet diverse application needs.Design/methodology/approachThe design involves a reconfigurable four-element microstrip antenna using FR4 substrate and copper patches. RF PIN diodes enable dynamic frequency, polarization and radiation pattern reconfiguration. Simulations and optimizations are performed using CST and HFSS, using techniques like the Nelder-Mead algorithm, particle swarm optimization, covariance matrix adaptation and trust region framework. An antenna prototype is also fabricated to validate the simulations.FindingsThe proposed antenna demonstrates significant reconfigurability: it switches between S-band (2.45 GHz, 2.52 GHz) and C-band (5.55 GHz, 5.59 GHz) with bandwidths of 120 MHz and 550 MHz, respectively. It transitions between circular and linear polarization in the S-band and modifies the radiation pattern by 45 degrees, providing an alternative radiation direction in the C-band. The antenna achieves a maximum gain of 5.95 dBi at 2.52 GHz and 93% efficiency at 5.55 GHz. Simulated results closely match those from the fabricated prototype, confirming the design’s validity.Originality/valueThe innovative use of RF PIN diodes enables comprehensive reconfigurability in frequency, polarization and radiation patterns within a single microstrip antenna, meeting the demands of S-band and C-band satellite communications. This study demonstrates superior performance, significant gains and efficiencies across various reconfiguration modes, validated by rigorous simulation and practical fabrication. The simple structural design further distinguishes this study from others in the field.

Multifrequency operation of an intracavitary monopole with sliding broadband choke for delivering hyperthermia treatment with variable coverage

ABSTRACT Microwave applicators reported for intracavitary hyperthermia (HT) operate at single frequency and deliver fixed treatment coverage at the tumor target. In this work, we report multifrequency operation of a water-cooled monopole antenna with a sliding broadband ferrite choke for delivering intracavitary HT to the cervix with variable spatial coverage. Spatially varying treatment coverage is achieved by varying the choke position with respect to the monopole using a mechanical sliding arrangement and exciting the antenna at the modified resonant frequency. Multifrequency operation of the antenna prototype is demonstrated over 700–1000 MHz using a straight intrauterine cervix applicator. Numerical simulations confirm the ability to deliver targeted HT with axial extent varying between 35.4 and 62.0 mm by controlling the sliding choke and coupling water temperature. Applicator prototype measurements in tissue mimicking phantoms confirm multifrequency operation of the antenna and its ability to induce axially varying intracavitary HT coverage to match the tumor size using a single applicator.

Gain improvement of HMSIW Antenna with SRRs

A novel integrated waveguide-backed cavity antenna, optimized for wireless communication systems operating at 5.8 GHz, is presented in this paper. The antenna design process is elaborated upon, emphasizing the incorporation of a high-gain substrate to enhance performance. At the target frequency of 5.8 GHz, the half-mode substrate integrated waveguide cavity antenna achieves a gain of 4.79 dB. Notably, the antenna design integrates two Split Ring Resonators strategically positioned at the periphery of the semi-circular patch to further augment gain. The design and simulation of antenna are done using high frequency software simulation version ANSYSEM17.2. Experimental validation of the simulation results is conducted through the fabrication of a prototype antenna, followed by rigorous performance evaluation using anechoic chamber and network analyser. Results demonstrate a significant enhancement in antenna gain, with the designed antenna exhibiting an analog gain of 11.15 dB at the specified frequency of 5.8 GHz, alongside an appreciable impedance bandwidth of 16 MHz.

Wideband circularly polarized patch array antenna with shared patches

AbstractIn this paper, a novel wideband circularly polarized (CP) array antenna is proposed. The array element is composed of four driven patches, four parasitic patches, and a loop feeding structure. On the basis of the array element structure, 1 × 2 and 2 × 2 arrays with shared patches are formed separately. Compared with the traditional structure, the volume of the 1 × 2 array antenna which only shares the patches in the x direction is reduced by 15%, and the volume of the 2 × 2 array antenna which shares the patches in the x and y directions is further reduced by 28%. The cleverness of this method is that it can keep the impedance bandwidth almost unchanged. To validate the simulated results, antenna prototypes are fabricated and measured. The results of the measurements demonstrate that the impedance bandwidths of the 1 × 2 and 2 × 2 array antennas are 27.2% (5.40–7.10 GHz) and 35.7% (5.22–7.49 GHz), respectively, and the 3 dB axial ratio (AR) bandwidths are 22.7% (5.31–6.67 GHz) and 25.4% (5.47–7.06 GHz), respectively. In addition, the measured data show that the 1 × 2 array exhibits a peak gain of 11.1 dBic, and the 2 × 2 array achieves a peak gain of 12.6 dBic. Both of them achieve a flat gain with a maximum ripple of less than 1.3 dB over the whole operating band.

Miniaturised ultra‐wideband circular polarised koch fractal crossed dipole array

AbstractUltra‐wideband (UWB) systems utilise a broad frequency spectrum to achieve high data transmission rates and enhanced precision, creating a demand for specialised UWB antennas. Circularly Polarised (CP) antennas are considered essential for maintaining robust performance under varied environmental conditions. Among them, the crossed dipole is effective for UWB CP applications, but its relatively large size could limit its use in various systems. A miniaturised crossed dipole design employing the Koch fractal structure is proposed and the measurement results are presented. The prototype antenna achieved an effective bandwidth covering 88% of the frequency range from 1.4 to 3.6 GHz. Additionally, a 4 × 4 array using this design was tested in the same frequency band, demonstrating beam‐steering capabilities up to 30°. The proposed antenna has demonstrated effective deployment in diverse communication systems and phased array applications within ultra‐wideband (UWB) CP environments.

A gain enhancement of compact UWB antenna based on a single FSS layer

AbstractThe present work introduces a novel low‐profile antenna for UWB applications through the use of a frequency‐selective surface (FSS). The FSS reflector uses a 7 × 7 array with a unit cell of 12.4 × 12.4 mm. By incorporating this periodic structure, the antenna's peak gain reaches 11 dBi, covering a UWB frequency range from 3.01 GHz to 13.5 GHz. Both FSS and UWB antennae are printed on the same type of substrate (FR4‐epoxy). The gap between the FSS layer and antenna is a half wavelength (18 mm) to obtain the best performance. The fabricated optimized antenna prototype shows a reasonable accord between numerical and experimental results. These results are compared to the existing literature designs. Overall, the proposed antenna system has reduced complexity and size, while offering a very wide bandwidth and high gain, making it a good candidate for imminent wideband and high‐gain wireless communication systems.